Grommet or core for tire beads



A. C. PRATT.

GROMMET 0R CORE FOR TIRE BEADS. APPLICATION FILED MAR. 25. 1919.

1,437,013, y Patented Nov. 28,1922.

INVENTOR BY f ' ATTORNEY,

Patented Nov. 2d, i922.. y

Y errar arri..

ALPHONSO COMSTOCK PRATT, 0F DEEP RIVER, CONNECTICUT, ASSIGNORVTO INTER- NATIONAL BEAD WIRE COMPANY, A CORPORATION 0F DELAWARE.

GROMMET OR CORE FOR TIRE Beans.

Application led March 25, 1919; Serial No. 285,123.

To all whom it my concern.'

Be it known that I, ALPHoNso CoMsTocx PRATT, a citizen of the United States, residing at Deep River, in the county of Middlesex, State of Connecticut, have invented eertaln new and useful Improvements in" Grommets or Cores'for Tire Beads; and I do hereby declare the following to be Va full, clear, andexaet description of the invention, such as will enable others skilled in the lart to which itappertains to make and' use the same; I

This invention relates to .grommets or cores for tire beadsfor use in the manufacture of shoes or casi for pneumatic tires, particularly those dlgs the straight side type. The invention is directed to the. provision of a grommet of an improved construction which may be manufactured at relatively low cost and with substantial uniformity, which possesses to afmarked degree the strength which is so desirable in a grommet for an automobile tire, and rwhich has a cross-sectional shape which is lofl special utility. y f The construction commonly employed for grommets .or cores for tire beads is one which includes a core and a plurality `of convolutions of wire wound spirally upon this core. Usually the core consists of a hoop made from a single strand of wire which is bent toacircular form .j andlthen has lits ends united any suitable manner as by welding them together. In some instances the core 'has been'lmade up from a plurality of strands of wire, the several strands lying side by side. l

In accordance withthe present invention,

the core for the grommet consistsY of three convolutions of wire laidside by side in such a relation as to :formv a triangular cross-section` the of the convolutions lie side by side and the third llies on the outer side of these two .coin-v volutions directly with the spirals o the several convolutions lying side the ends thereof 'may termined by the cross-sectional enclosed core, that isa shape approxlmatmg v especially section arrangement being such that two.

A. plurality ofl convolutions of spirals are` Ywound u on the core so fornid Hb,

'as by side and forming a complete layellor cas l ing. y.The surrounding layer or layers of' convolutions of spirals may be applied to the core in any suitable manner and the Iend 0r be secured in position 1n any suitable manner. y

After the grommetahas been so formed, it is preferably stretched to enlarge it to the precise` diameter desired. for the `completed grommet. During this process 0f expanding the grommet. to the desired size,l

the surrounding casing or casings of spirally. formed wires, which initially had a configuration approximating a circle in cross-section, Vassume relative positions deshape of the a triangle having one of its sides toward the center of the rected outwardly.

y This form of grommetgis desirable for use iny casings for automobile tires, v heavy vehicles such as trucks.

In the accompanying drawings, Fig. 1 is an elevation of a grommet; Fig. 2 is a crossof a grommet embodyingthe present inventionv prior to being expanded; Fig; 3 is 'a View similar to Fig. `2 showing the grommet after it has been expanded; Fig. 4 is an enlarged view of a portion of the grommet; and Fig. 5 is a `sectional detail view illustrating a modification of the construction` shown in the other figures.

Referring to these drawingsgthe'groinrnet shown 'consists cfa core and a single layer 'of spirals enclosing this core. The core conslsts of three ,convolutions of wire.. rI`hese three convolutions ,are designated 6, 7 and 8 on'FigvQ. It willbenoted that the convoand towardV lutions 6 and 7 jliesfide'by side the center ofthe grommet while the convo- The three convolutions thus arranged form a core which vis of triangular cross-sectiom The three convolutions 6,7 and 8 are preferably formed from a continuous piece, ofwire which may be integralwithA or ,separate from the wire formi the'su ,ritnposed layer or layers of spirgs.' wire from which the convo uhe cof formed is separate from l, i teasing of spirals, the ends of this pieceo wire may be ioined if desired, welding'tl'iem' 'togethe' r the cone-has been formed as above those convolutions.

grommet and its apex diparticularly tires for- `95 -lutlon 8 lies on the outer side ofthe convolutions and 7 over the adjacent sides of 'cross-sectional shape of described, the layer of spirals is applied to it as shown at 9. For this purpose wire is woundl spirally upon the core, a plurality of convolutionsv of the winding being employed and the spirals of the several convolutions lying side by side upon the surface of the core.' `This may be done in any suitable manner, the wire Yof the surrounding casing being given its spiral form either as an incident to applving it to the core or previous to the application of the wire to the core. The end of the wire forming the surrounding casing of spirals may be secured in positlon in any suitable manner.

When this surrounding casing of spirally formed wire has been completed, the grommet is in substantally the form indicated in Fig. 2, the sp-irals of the casing being arranged approximately in a circle about the triangular core.

The grommet so lformed is then subiect ed to heavy rassure to expand it to the' desired size. hile so expanding the grommet, the casing of spirals assumes a configuration more or less approximating the the core so that the completed g'rommet is substantially triangular in cross-section. The relation of the core wires'and the wires of the spiral casingafter the grommet has been so expanded, is indicated in' Fig. 3.

It will be noted that the wire of all of the convolutions is shown as of the same diameter. It desired, however, the core and the casing may be formed from separate pieces of wire; where greater strength is desired, the core may be formed from a separate piece of wire which is of larger cross-section than the wire for the spiral casing. Such a construction is illustrated in Eig. 5 wherein the core wires 10 'are of considerably greater diameter than the casin wires 11.

7Vhat I claim is:

1. A grommet having a core and a casing on the core consisting of a plurality of convolutions of spirals with the spirals of the several convolutions lying side by side, the said core consisting of three convolutions of wire lying side by sidey to form ya core of triangular cross-section.

2. grommet having a core consisting of three Wires arranged in the form of a triangle and a casing on the core consisting of l a plurality of convolutions of spirals with 56 the spirals of the several convolutions lying side by side. l

3. A circular grommet having a core consisting of three convolutions of wire laid together so that each contacts with the other two to form a core which is substantially triangular in cross-section and a easing on the core consisting of a plurality of convolutions of spirals with the spirals of the several convolutions lying side by side, the grommet being substantlally triangular in cross-section and having one of the sides of the triangle rtoward the center of the circle of the grommet and the .apex of the triangle opposite that side directed away from that center.

4. A circular grommet formed from a continuons vpiece of wire and consisting of a core -forned of a plurality of convolutions of substan ially straight lengths of wire lyside by side and. `a casing infr thi; core formed from a plurality vvolutions of. spirals with the spirals of the several convolutions lying side by side and encircling the core, the grommet being substantially triangular in4 cross-section and havlng one of the sides of the triangle toward the center ofthe circle of the grommet and the apex of the triangle opposite that side directed away from that center.

5. A circular grommet formed; from a continuous piece of wire and consisting of a core formed from three covolu-tions of the wire and a casing formed from a plurality of convolutions of spirals of the wire with the spirals of the several convolutions lying sideby side, the three convolutions constituting the core being arranged in the form of a triangle and the completed grommet being of triangular cross-section with 95 one of the sides of the triangle toward the center of the circle of the grommet and the apex of the triangle directed away from that cent/er.` v

In ltestimony whereof I aix my signature. 100

ALrHoNso coMsTo'cK PRATT. 

